Painting process and composition therefor



106. coMPosmons,

III

COATING 0R PLASTIC.

Nov, 1 7777 Cross Reference m1 E sm-1-Es PATENT- OFFICE.

"I min towns, or 'Bnooxmm, NEW YORK.

' v r'nnirmc rnocnss am) No Drawing.

This invention relates to painting processes andcompositions thereforand it comprises a process of painting and protecting rusty ironandsteel, and particularly metal used for oil tanks and the like, whereinthe iron if not already rusty is allowed or caused to rust and. istreated with a coating composition comprising an emulsified mixture oflinseed oil soap, water and an alkaline casein composition and variouspigments, these pigments including a certain amount of whiting and ofzinc oxid thereby forming a. coating composition whereof the rust on theiron forms an integral part; and it further comprises a compositionadapted for use in the stated process and'comprising linseed oil soap,water, casein (usually brought into solution with sodium silicate), zincoxid, -whiting and such pigments a's may-be desired; all as more fullyhereinafter set forth and as claimed.

Protection oi iron gpis teelggainst eg rosion and rus ing isfifi course,a great problem, and particularly in the case of tanks,

- etc.,'used for gasoline and oils, both mineral Ordinary oil paints,bituminous varnishes, etc., are here inapplicable. Many compositionshave been de: vised and used for protecting iron and steel oils andfatty oils.

against corrosion. To a great extent, however, they do not serve thedesired purpose, and in any event they are not considered applicable torusted surfaces; or to oil tanks and the like. It is a well recognizedfact that rusting once initiated tends to continue probably by theinstitution of a. galvanic couple with the unattacked-metal. Most of theordinary types of paint coatings are more or less porous or tend tobecome so in time and with rust in contact with the iron, access ofmoisture tends to increase the amount of rust. It is therefore the usualpractice in painting iron which is rusty to remove the rust asapreliminary. The iron or steel, for example, is cleaned by sandblasting or scratch brushing as a preliminary to painting. It isconsidered bad practice to allow any rust whatever to remain on thesurface to be painted. p

In the preesnt invention I attack the problem of protecting rusty ironagainst further corrosion b making the rust itself an integral portionof a protective coating. Instead of being a detriment, the rust is anadvantage. Iron does not usually rust or corrode in alkaline media and Imake my procomrosrrron riinnnron.

Application filed larch 10, 1924. Serial No. 698,285. /0 6 7 tectivecomposition of an alkaline character.

And that it may penetrate rust I use a certam :amount of water in thecomposition; making it-an emulsion, I find in practice that it isdesirable to .use linseed oil, or a similar drying oil, such as I u w wfish Oll etc., as a component of the composi- Ition. llln the presenceof thgalkali, as which usua y emp oy caustic so a the oil is more orless saponified, iormmg the corresponding As another component oi' them1xture l employ casein brought in solution by a suitable alkaline body;this body being usually commercial silicate of soda or water glasssodium siligatel. Ki 1d l find that the presence -0 a certain amount ofzinc oxid d of desirab ea he1 w 0 e Cinmture 1s a sort of compoun emu s',an is a lied b 1 mini;- ing on the suriace to be gi'otecteil. Theemulsion enters and permeates the rust and comes into actual contactwith the iron; the rust forming a part of the body of the coatng. It theiron is not already rusty, or is lnsuiiimently rusty, it'- isadvantageous to glVG it a rehminary treatment whereby rust 1s forme Themetal may be preliminarily brushed with a little acid, a solution ofsalammonlac, etc.

Qompositions of the type of that just described have the greatadditional advantage that they resist the solvent and disintegratngaction of gasoline and of the various mineral oils and fatty oils, andtherefore afford a means of protecting oil tanks and like apparatus. Thecomposition is particularly useful in the interior .parts of such tanks.Such a composition furthermore gives an s gtiasgtg m iwhlw haltcompositions Eothat for outside work, w ere i is no a question ofresisting oil, etc. rusted metal may be coated with such a mm 1n taininlin eed oil soaps, as well as un- Fadded.

char rged linseed oil. I further dissolve a out a pount s 0 commercialcasein in about 4 gallons of water co'nTaTfiiii'g Tjmund of commercial wrs and mix this withthe first solution, stirring intimately to producegood admixture. To the mixture thus produced may be added lS poundsofwhitmand the same quantity of commercia zinc oxid. Four or five poundsof tintim i men f any desired character -m21' be urt ier added.

The whole composition made as just described is a thick paint-like mass.It may be ground in the usual type of paint mills. If it be desired tostore the material for long periods. a small amount of a prcscrv tire,such as phenol salicvli id. etc.. may

In spiteo 1ts t nc the composition has av great spreading power onmetals and when it is applied to a rusty iron or steel surface, itpenetrates the rust. reaching the metal. As itsets, or dries. the rustbecomes an integral part of the coating. With well rusted iron the firstcoating ordinarily red in color, the intensity being in proportion tothe thickness of the rust. The more rust there is on the surface. thebetter the protection will be. The mixture is strongly adhesive andclings firmly to the metal. Its adherence. however. to rusted metal ismuch better than its adherence to clean metal.

As to what chemical reactions ensue in the manufacture and drying ofthis paint among the described components and between them, or theirreaction products and the iron rust. I am not prepared to say. I maynote. however, that, as stated, in the dried paint film the oxid ofiron, or rust, is a component and it no longer has its usual power ofdeveloping further rust on the metal; possibly because itis spaced awayfrom the metal by penetration of liquid therebetween and possiblybecause the oxid no longer exists in its orginal physical form. Thewhiting and Zinc oxid appear to be highly advantageous bodies in thecomposition and in the process; perhaps because of reaction with thesoap and the casein. as well as the silica, if present. with formationof insoluble compounds. Whatever the reasons may be, on rusty iron andsteel the composition forms an unusually hard and resistant non-perriouscoating. It is non-porous and does not allow access of water to theunderlying metal. The

coating is further insoluble in oils. even resisting gasoline. It thusfinds its chief application for the coating of oil storage tanks. which,up to the present time. hare not'been successfully protected againstcorrosion. and it is for this purpose that the protective properties ofthis coating find their greatest usefulness.

1 01' outside work and the protection of surfaces exposed to the weatherwhich are toreceive asphalt or paint coatings. the new process may beemployed in lieu of sand blasting or scratch brushing as a preliminaryto such painting. The surface, in lieu of being cleaned to free it ofrust. is simply coated with the present composition and thereafterpainted in the usual way.

l -fhat 1 claim is 1. The process of protecting rusty iron with anoil-proof coating containing iron cium compounds, linseed oil soaps andcasein to form a coating carrying the rust of the metal as an integralcomponent.

2. The process of protecting iron and steel which comprises rusting themetal and thereafter applying a coating containing insoluble zinc andcalcium compounds. linseed oil soap and casein. to form a coatingcarrying the rust of the metal as an integral com ponent. V

3. The process of protecting rusty iron which comprises applying torusty iron a composition containing linseed oil soaps. casein. silicateof soda. zinc oxid and whiting: all as an aqueous suspension andsolution.

4. The process of protecting the interior of rusty iron or steel tanksused for the storage of gasoline. mineral oils, animal and ycgetahleoils, etc.. by applying to rusted surfaces thereof a compositioncontaining linseed oil soap-s. casein. silicate of soda Zinc oxid andwhiting; all as an aqueous suspension and solution.

5. As a new composition of matter for protecting rusty iron, a pastycomposition of alkaline reaction containing water. zinc nd calciumcompounds. linseed oil soaps. silicate of soda and casein. I

In testimony whereof, I have hereunto affixed my signature.

ALLEN ROGERS.

